Apparatus for lining centrifugal casting molds



K. R. DANIEL ETAL APPARATUS FOR LINING CENTRIFUGAL CASTING MOLDS FiledDec. 28, 1955 Feb, 17, 1959 9 Sheets-Sheet 1 m o B OLR E m m Yum... n rmY A mM H n Nsw NEN m m MS Y B w Fm? 7, 1959 K. R. DANIEL ETAL I2,873,716

APPARATUS FOR LINING CENTRIFUGAL CASTING MOLDS Filed Dec. 28 1955 9Sheets-Sheet 2 0 Q: m| M g a g s g (R I Q i "3 6 r g s k A INVENTORSKENNETH R. DAN/EL Q JAMES 0. P4 rro/v, JR.

STANLEY 1 VINE 8 W fi dmhidfm ATTORNEYS Feb. 17, 1959 K. R. DANIEL ETAL2,873,716

APPARATUS FOR LINING CENTRIFUGAL CASTING MOLDS JAMES 0. PA TTO/V, JR.

STANLEY l. WIVES ATTORNEYS Feb. 17, 1959 K. R. DANIEL ETAL' APPARATUSFOR LINING CENTRIFUGAL CASTING MOLDS Filed Dec. 28, 1955 9 Sheets-Sheet4 INVENTORS mm MM DTW R DAIV m .r o: L. NS N F- A EMT K S BY W /WMLzwATTORNEYS Feb. 17, 1959 K. R. DANlEL ETAL 2,873,716

APPARATUS FOR LINING CENTRIFUGAL CASTING MOLDS Filed Dec. 28, 1955 9Sheets-Sheet 5 Elm.

INVENTORS KENNETH R. DAN/E L JAMES 0. PA TTO/V, JR. STANLEY V. WIVESATTORNEYS Feb. 17, 1959 K. R. DANIEL ET AL APPARATUS FOR LININGCENTRIFUGAL CASTING MOLDS Filed Dec. 28, 1955 9 SheetS-Sheet 6 INVENTORSKENNETH R. DAN/EL JAMES 0. PATTON, JR. STANLEY l! WIVES BY WWYMMATTORNEYS Feb. 17, 1959 K. DANIEL ET AL APPARATUS FOR LINING CENTRIFUGALCASTING MOLDS Filed Dec. 28, 1955 9 Sheets-Sheet 7 Y B W WMEMw-wATTORNEYS Feb. 17, 1959 K. R. DANIEL ETAL 2,873,716

APPARATUS FOR L'INING CENTRIFUGAL CASTING MOLDS Filed Dec. 28, 1955 9Sheets-Sheet 9 230 Mac. A

AIR L I HYDRAULIC FLU/D AIR 1NVENT( RS KENNETH R. DAN/El. JAMES 0. PA 7'TON, JR.

STANLEY l. V/NES BY W 414M414; rm

ATTORNEYS APPARATUS FOR LINING CENTRIFUGAL CASTING MOLDS Y KennethR.Daniel, James 0. Patton, Jr., and Stanley V. Vines, Birmingham, Ala.,assignors to American Cast Iron Pipe Company, Birmingham, Ala., acorporation of Georgia Application December 28, 1955, Serial No. 555,934

24 Claims. Cl. 118-55) This invention relates to apparatus for liningmetal molds used in the centrifugal casting of tubular metal articles,and is particularly directed to mechanism for forming refractory liningsin vented metal molds in accordance with the method disclosed in theapplication of Frank H. Coupland et al., Serial No. 446,488, filed July29,1954, now Patent No. 2,731,690, granted January 24, 1956.

are two conventional centrifugal casting procedures: the de Lavaudprocess wherein the metal is cast directly against the inner surface ofan unvented, water-cooled metal mold and a chilled casting is producedwhich must be annealed; and the Sandspun method which uses a vented moldhaving a green sand lining of from one to two inches in thickness andproduces an unchilled casting requiring no annealing. In comparison withthese old processes, the characteristic feature of the Coupland et al.method is the use of a vented metal mold having a smooth, dense resinbonded sand lining of uniform and accurately controlled thickness which,although much thinner than the green sand lining of the Sandspunprocedure, is effective to avoid unduly rapid freezing of the castingmetal while at the same time materially reducing the casting time.

The principal object of the present invention is to provide new andimproved apparatus for lining vented metal molds with resin bondedrefractory linings of the character employed in the above-mentionedCoupland et a1. method of centrifugally casting tubular metal articles.

Another object is to provide a novel mold lining mech- United StatesPatent As pointed out in the Coupland et al. application, there anismwhich is adjustable for use with molds of different which cooperate todeliver into the mold an accurately' measured quantity of liningmaterial, and novel means for preventing the lining material fromadhering to certain predetermined areas of the mold.

A still further object is to provide a pair of commonly controlledlining machines which are adapted to form successive layers of resinbonded refractory lining in a metal mold at adjacent lining stations.

These and other objects, including the provision of means forautomatically controlling the sequence of operations of mold liningapparatus of the character described, will appear more fully uponconsiderationof the detailed description of the embodiment of theinvention which follows. In this connection, although only one specificform of lining apparatus is described and illustrated in theaccompanying drawings, it is to be expressly understood that thesedrawings are for purposes of illustration only and are not to beconstrued as defining the limits of the invention, for which latterpurpose reference should be had to the appended claims. A

In general, the apparatus of the present invention com prises twomachines of substantially identical construction arranged in tandem atadjacent stations of a centrifugal casting production line, the twomachines being adapted to form successive layers of a resin bondedrefractory lining in a vented metal mold while 'the mold is beingrotated at a predetermined speed. Each lining machine includes a moldsupporting and rotating mechanism; a trough which is movable axiallyinto and out of the mold, and rotatable about its axis while within themold, for delivering the lining material into the mold; means forplacing in the trough an accurately measured quantity of the liningmaterial; mechanism for adjusting the elevation of the lining trough soas to properly align it with molds of different sizes; and means forpreventing the lining material from adhering to certain areas of themold where a bonded lining is not desired. The apparatus also comprisesa system of switches, relays, valves,

fluid pressure cylinders and other elements which auto-.

matically controls thesequence of operations of each lining machine, andinterlocks the two machines to insure simultaneous unloading of the moldsupporting and rotating mechanisms. It will be obvious, of course,.thatthe apparatus of the present invention is readily adaptable tothe'formation of single layer, instead of twozlayer, linings either byomitting the second lining machine from the.

assembly line, or by lining two molds at a time and then dischargingboth linedmolds from the apparatus before again starting thelining-cycle.

Inasmuch as the apparatus of the invention is especially well adaptedfor use in the manufacture of cast iron pipe, the followingdisclosurewill be directed .primarily to this particular application ofthe inventive concept. By so doing, however, it is not intended to limitthe scope of the invention to mechanism for lining pipe casting molds,because it will'be evident that the apparatus also has utility inconnection with molds for producing other forms of castings.

In the drawings, wherein for illustrative purposes the molds are assumedto be of the type used for centrifugally casting bell and spigot pipe bythe previously mentioned Coupland et al. process (although the vents inthe mold walls are not shown in the drawings), and wherein likereference characters indicate like parts throughout the several views:

Figs. l and 2 are somewhat diagrammatic plan and side views,respectively, of one form of apparatus for lining metal pipe castingmolds in accordance with the present invention, certain of the elementsof the machine having been, omitted in the interest of simplicity;

Fig. 3 is an enlarged side view of the mold supporting and rotatingmechanism of one of the machines; of Fig. 1; Fig. 4 is a plan viewcorresponding to Fig. 3 with the central portion of themold on thespinning rollers broken away'so as to moreclearly illustrate certainfeatures of the construction; r

Fig. 5 is a' cross section taken substantially on line 5-5 in Fig. 4,showing the means by which molds are delivered to and discharged fromthe rotating mechanism, the. parts being shown in the positions occupiedwhen a mold is being rotated;

Fig. '6 is a cross sectional view similar to Fig. 5, but showing theparts in the positions occupied when a lined mold is being dischargedand an unlined mold is being delivered to the rotating mechanism;

Fig. '7'- is an enlarged side view, broken. at several points along thelength thereof, of that part of one of I the machines of Fig. 1, shownat the left-hand side of Patented Feb. 17, 1959 a saidfigure, by whichan accurately measured quantity of lining materialis delivered into'amold while it is being rotated by the mechanism shown at the right-handside of Fig. 1;

Fig. 8 is a plan" view correspondingto'theside 'view of Fig; 7, withmost of the lining'trough broken away in order to more clearlyillustrate theparts lyingtherebe-- neath;

Fig. 9 is a partially, sectioned side view one still larger scale ofthemeans by which the lining trough and associated elements are adjustedin elevation in order to oper ate with molds of different diameters;

Fig. 10 is a plan view corresponding to-Fig. 9 sectioned substantiallyon the line10--10"in the latter figure;

Figs. 11 and 12 are side and end views, respectively, of the front endof the lining trough and the associated means 'by which the liningmaterial is delivered'to the" trough in accurately meaured amounts;

Fig. 13 is an enlarged cross section-taken substantially on line 13-13in Fig. 11, showing the construction of the'lining trough;

Fig. 14 is a fragmentary plan view'of the frontend of the striker deviceby which excess lining material is removed from the trough;

Fig. 15 is a vertical cross section taken substantially on line 1515 inFig. 14, showing the shape of the striker.

plate;

Fig. 16 is a side view corresponding to Figs. 14 and 15;

Fig. 17 is a fragmentary side view on a still larger scale of theright-hand end of the mechanism shown in Fig. 3, showing in operativeposition the means by which the lining material is prevented-fromadhering to certain surfaces of the mold bell;

Fig. 18 is a simplified schematic diagram of the electrical controlsystem for the two mold lining machines indicated in Fig. 1, showing thepositions of the various switches and relays in their at rest orinoperative condition,i. e., when both lining machinesare empty awaitingthe delivery of molds to the supporting and rotating mechanisms thereof;I

Fig. 19 is a simplified schematic diagram of the electrical circuit ofone of the motors which drives the mold rotating mechanisms; and

Fig. 20 is a schematic diagram illustrating the supply of air andhydraulic fluid to various elements of one machine.

As indicated in Fig. 1, the apparatus of the present invention comprisesa pair of lining machines L and L located closely adjacent one anotherin tandam relationship with their principal axes perpendicularto therails 31 of a mold run on which molds 32 may be rolled to and from thelining machines by gravity, in the direction indicated by the arrows inFig. 1. Although in practicing the .Coupland et al. process machines "Land L may be used to form successive lining layers of slightlyditfer'ent sand-resin mixtures in each mold, the construction andoperation of both machines are identical. Accordingly, except for theinterlocking feature of the electrical control system shown in Fig. 18,only one of the machines, L will be described.

Referring first to the generalized showing of Pigs.,1 and 2, theprincipalelements of each machine include a mold rotating mechanism 33,a lining trough 34 adapted to receive a measuredvquantity ofsand-resinlining material 'froma hopper-SS'and to deliver it intomold32- while the latter is being rotated by mechanism 33, a lin-' ingcar 36 by which trough '34'is supported and moved axially intoand out ofmold 32, a vertically'movable frame 37 on which lining car 36 is movablysupported, a mechanismindicated generally at 38 for-'adjus'tingtheelevation of frame 37, and a device'indicated.generally at 39 associatedwith mold rotatingmechanism .33 by which the lining material may beprevented from, ad-- hering to certain surfaces .ofthebell endof-themold.

Turning now to the mold rotating mechanism 33,

shown best in Figs; 3-6, a plurality of spinning rollers 40' areprovided for supporting and rotating mold 32 in a horizontal positionduring the lining operation, said rollers being mounted in two sets onshafts 41 and 42 which extend parallel to the axis of the mold and arejournaled in bearings 43 mounted on a stationary base 44 suitably fixedto the machine foundation. In the embodiment illustrated, shaft 41 isadapted to be driven by a variable speed motor'45 while shaft 42 is anidler, the rollers on In order to properly control'the delivery anddischarge.

of molds to and from spinning rollers 40, mold rotating mechanism 33includes a pair of parallel, axially spaced detent-guide arms 48 whichcontrol the delivery of molds to said mechanism, and a cooperating pairof kickout arms 49 the primary purpose of which is 'to'eject the moldsfrom the machine after they have been lined.

As indicated in Fig. 4, kickout arms 49 are-fixed to the endsof a torquetube 50 which is mounted for oscillatorymovement about a fixed axisparallel to the axes of spinning roller shafts 41 and 42 at a positionbeneath the-ends of mold run rails 31 at the discharge side of themachine. The upper surface of eachkickout arm 49 is of bent shape,having a portion 51 which is substantially tangent to the upper surfaceof torque tube Stland a second portion 52 which is inclined downwardlyrelative to radially extending portion 51, and'terminates in an'upwardly extending pointed end portion 53 which projects slightly beyondthe vertical axial plane of mold32; toward the side of the machine fromwhich the molds'are loaded, when the mold is in spinning position onrollers 40. 1

Each of detent-guidearms 48 is provided with a clevis shaped inner endpivotally connected to the free end of the associated kickout arm 49-bya pin 54'at a point just below the junction betweenpointed-end portion53 and inclined portion 52 of the kickout arm, and is also of irregularshape- As shown in Figs. 5 and 6, the upper "surface of eachdetent-guide arm 48 is bent at substantially the same angle as the uppersurface of kickout arm 4,-having a portion 55'at the outer end of thearm which is inclined downwardly with respect to the portion 56 at theinner end-of said arm.- The bottom edge of each detent-guide-arm 48rests on a flanged roller 57 rotatably mounted in a bearing bracket-58"fixed to base 44. Rollers 57 engage'the bottom edges of detent-guidearms 48 at pointssubstantially directly beneath'the junc-- tions betweensurfaces-55 and-56,and-supportsaid arms in a position such that saidjunctions lie in approximately the sameplane as the rolling surfaces ofrails 31. The twodetent-guide arms 48 are interconnected by a tie tubeor rod 59 at points intermediate the axes of flanged rollers 57 and theinner ends-of said arms where'they are pivoted to kickout arms 49, tietube 59 extending parallel to torque tube 50. 7

Fixed to torque tuhe-Stl'intermediate its ends is a radially extendingoperating-arm 60' which lies in sub stantially the same plane as kickoutarms 43 and is pivotally connected at its inner end to the upper end ofthe piston 61 of a hydraulic cylinder 52. Cylinder 62 extends downwardlythrough a central opening in the base 44 ofmold rotatingmechanism'33 andis provided at its loweriend with a base cap 63 which is pivotallyconnected to a supporting bracket 64 fixed to the machine foundation.

When a mold is in lining position on spinning rollers 40, piston 61 ofhydraulic cylinder 62 is in its fully retracted position anddetent-guide arms 48 and kickout arms 49 form a wide V, as indicated inFig. 5, with their upper surfaces completely out of contact with thesurface of mold 32. At this time, the outer ends of detentguide arms 48project upwardly above the rolling surfaces of rails 31 in such positionas to prevent the next mold on the delivery side of the machine fromentering the mold rotating mechanism.

When the mold on rollers 40 has been lined, it is ejected or dischargedfrom the machine by admitting hydraulic fluid to cylinder 62 so as toraise piston 61 to the uppermost position permitted by adjustable stopnuts 65 which are threaded on rods 66 depending from the upper end ofsaid piston and passing through openings in the cylinder head. Theupward motion of piston 61 is transmitted by operating arm 60 to torquetube 50 and results in a counterclockwise rotation of the latter andmovement of kickout arms 49 to the position indicated in Fig. 6. Askickout arms 49 are raised from the position shown in Fig. 5, theirpointed end portions 53 and inclined surfaces 52 come into contact withthe surface of mold 32 at points on opposite sides of the vertical axialplane thereof, raise the mold, and then, as inclined surfaces 52 riseabove the level of the rolling surfaces of rails 31, roll the mold offthe kickout arms and onto said rails, as indicated in Fig. 6.

Due to the pivoted connection between kickout arms 49 and detent-guidearms 48, elevation of the former also raises the inner portions of thelatter to a substantially horizontal position, level with rails 31, andlowers the outer ends thereof below the rolling surfaces of the rails sothat the next mold in line may roll into the machine to the positionindicated in broken lines in Fig. 6, where the pointed ends of kickoutarms 49 hold the mold until it is lowered onto rollers 40 when hydrauliccylinder 62 is exhausted and piston 61 returns to the retracted positionshown in Fig. 5. As the inner ends of detent-guide arms 48 are raised byvirtue of their pinned connection with the ends of kickout arms 49,rollers,5.7 permit arms 48 to adjust their positions accordingly,forming in effect movable fulcrums.

As will beexplained hereinafter in connection with the automatic controlsystem of the lining machine, retraction of piston 61 is accomplishedautomatically as the result of actuation of a kickout down limit switchLS1 which is positioned alongside one of rails 31 closely adjacent theend of said rail from which the mold rolls into the lining machine, andthe operating lever of which is depressed by the mold as it rollsthereover.

Turning now to the mechanism by which the lining material is measuredand delivered into the mold 32 as it is being supported and rotated withits axis in a fixed horizontal position, i. e., the means shown atthe-lefthand sides of Figs. 1 and 2, it will be seen best from Figs. 7and 8 that car 36 which supports lining trough 34 is provided with twopairs of wheels 67 running on tracks 68 fixed to the upper surfaces ofthe side members of vertically movable frame 37. Mounted at the rear endof car 36 is a variable speed, reversible, three phase A. C. motor 69the shaft of which extends transversely of the frame parallel to theaxle 70 of the rear pair of wheels 67, and is drivably connected to saidaxle by a chain and sprocket drive 71. Axle 70 is in turn drivablyconnected to the axle 70' of the front pair of wheels 67 by a chain andsprocket drive 89 which includes a pair of idler sprockets 90 so mountedas to be adjustable forwardly or rearwardly for the purpose of taking upslack in the chain.

The forward end of car 36 carries a pair of axially spaced bearings 72which rotatably support an enlarged cylindrical barrel 73 fixed to therear end of lining trough 34. Intermediate car driving motor 69 andtrough bearings 72 the car carries a reversible, three phase A. C. motor74 and a speed reduction gear 75 which are drivably connected to barrel73 of trough 34 for the purpose of slowly rotating the trough through anarc of approximately 180 so as to dump the contents thereof into themold after the trough has been moved into the mold by a forward movementof'car 36 from the normal, at rest position indicated in the drawings tothe forward end of frame 37.

Asbest illustrated in Figs. 11 and 13, trough 34 comprises a bodyportion 76, substantially rectangular in cross section and open at thetop, which is adapted to receive the lining material from hopper 35through a nozzle 77 and an automatically controlled gate 78, and astiffening base member 79 in the form of a I-beam which extends the fulllength of and is welded to body portion 76. At theforward end of thetrough, the bottom portion of base member 79 is cut away and the thusreduced end of the trough is fitted with a cylindrical nose piece 80having a conically shaped end 81. In order to assist in maintainingtrough 34 in a horizontal position as it moves into and out of the mold,the forward end of frame 37 is provided with a pair of bearing brackets82 rotatably supporting a roller 83 on which trough nose piece 80 restswhen the trough is in its rearmost position trough at the properelevation for the size of mold be-' as shown in the drawings. In orderthat the bottom flange of trough base 79 may be guided onto roller 83 asthe trough moves forwardly, a wedge-shaped fillet plate 84 is fixed tothe rear portion of the bottom surface of nose piece abutting thecut-away portion of base member 79.

The bottom flange of base member 79 is also cut away at the rear end ofthe trough so as to receive a cylindrical sleeve 85 which is welded tothe trough and fixedly connects the latter to the enlarged barrel 73journaled in bearings 72. At a point just forward of sleeve 85, troughbody portion 76 is provided with a transverse end plate 86 (Figs. 7, 8and 13) which defines the rear end of the open portion of the troughintended to carry the lining material, and with a triangular plate 87,perpendicular to s and extending forwardly from end plate 86 centrallyof With thestructure thus far described, it is evident that liningtrough34 may be moved by car 36 axially into and out of a mold 32 as thelatter is being supported and rotated by the mechanism indicatedgenerally at 33. As trough 34 is moved forwardly into the mold, it ismaintained in a horizontal position both by supporting roller 83 and bythe stitfness of I-beam base member 79. most position and extendsentirely through the mold, the conical end 81 of trough nose piece 80comes into contact with a substantially semiconical trough guide 88(Figs. 3, 4 and 17) which is mounted on the framework 126 of bellcleaning device 39 closely adjacent the bell portion of mold 32. Troughguide 88 is so mounted that its position may be adjusted for molds ofdiiferent diameters in order to support the front end of the ing lined.It is also evident from the preceding description that, when the troughhas been moved into the mold, it may be rotated by motor 74 and speedreduction gear 75 so as to dump its contents into the mold. After thetrough has been inverted, it is automatically returned to its normalupright position by a reversal of motor 74 by the control system laterto be described.

Referring now to the mechanism, including nozzle 77 and gate 78, bywhich an accurately measured quantity of sand-resin lining material isdelivered into open-top trough body 76 from hopper 35 as the liningtrough is moved axially into a spinning mold, it should first be notedthat hopper 35 is mounted in a permanently fixed position, as bysuspension from overhead beams 91 (Fig. 2). Nozzle 77 and gate 78,however, are carried by a framework'92 which is mounted on and extendsupwardly When the trough has been advanced to its forwardfromvertically-movable:frame 37 'at the forward end thereof-,rthe open-topof nozzle 77 beingso positioned as to receive the'discharge end ofhopper 35.

As shown in Figs. 11-16, gate 78 comprises-a pair of sector-shaped sidewalls 93 and a curved bottom end wall 94 interconnecting the arcuateedgesof side walls 93, end wall 94 having a discharge opening 95-therein which extends from its upper edge (as viewedin Fig. 11)downwardly for approximately half the arcuate extent of said end wall,the side edges of said opening being parallel to and spaced inwardlyfrom side walls 93 so as to form a laterally restricted exit from thenozzle. Side walls 93 of the gate are rotatably mounted on studs 96carried by the side walls of nozzle '77, the pivotal axis of studs 96passing through the centers of the areu-ate edges of the gate. Fixed togate 'end wall 94 beneath opening 95 is a spout 97 having downwardlyconverging sides by which the lining material discharged from nozzle 77through gate opening 95 is guided into trough 3-4. The rate of flow ofthe sand-resin mixture out ofnozzle 77 may be varied by adjustment of aninclined bafiie plate 166 which is slidably mounted within the nozzleand has an outwardly projecting arm 167 adjustably fixed by a pair ofnuts 168 to a threaded supporting rod 169 suitably mounted on therearwall of nozzle 77.

The position of gate 78 is controlled by a pneumatic cylinder 98 fixedlymounted on framework 92 with its axis inclined to the vertical, andhaving a downwardly extending piston 99 the lower end of which ispivotally connected to a lug'100 fixed to one of gate side walls 93; Thegate is normally maintained in the position indicated in Figs. 11 and12, where in the solid'portion of end wall 94 closes the opening at thebottom end of nozzle 77. When pneumatic cylinder 98 is actuated so as toretract piston 99, gate 78 is moved in a clockwise direction about theaxis of studs 96 so as to bring discharge opening 95 of end wall 94 intoregistration with the open bottom end of nozzle 77, whereupon thesand-resin lining mixture may flow by gravity through spout 97 intotrough 34.

Inasmuch as the thickness of the lining formed in the spinning moldisdetermined directly by the amount of lining material delivered bythetroughinto the mold, it is necessary to accurately measure the amount ofsuch material held by the trough. In accordance with the presentinvention, this measurement is made by controlling the depth or heightof the lining material in the trough and by removing any materialdelivered to the trough in excess of that required toestablish theproper depth or height.

In the embodiment illustrated, the measuring means .comprises a strikerplate101 adapted to be lowered into trough 34 by a pair of arms 102,normally maintained in a substantially horizontal position, the rearends of which arepivotally mounted on a shaft 103 carried by a bracket104-fixed to framework 92. Fixed to the forward ends of arms 102 is asupporting member 105, substantially U-shaped in plan, having at therear ends of the side arms of the U a pair of notches 106 adapted toreceive the stepped ends 107 of the upper portion of striker plate 101.The striker plate is secured in position in notches 106 by a washer 108which is retained in engagement with the upper edge of the striker plateby a screw 109 threaded into-supporting member 105. Extending downwardlyfrom the stepped end portion of the striker plate is a tongue portion110 which is adapted to enter the lining trough and to establish thedepth of the lining material retained therein by the position of itslower edge 111.

It will be understood that the width and length of tongue portion 110 ofstriker plate 101 are accurately dimen sioned in relation to'the widthand depth of trough body portion' 76 so that the space within the troughbelow the lower edge 111 of the striker plate when the latter hasentered the'trough will hold the correct amount of lining material toform a lining of the thickness desired. It willv P also be evidentthatstrikerplateltll-.is readilyreplaceable by other striker plates ofdiffefentdimensions-which are adapted toretain different amounts oflining material in the.trough.-.

Striker plate 101 and its supporting arms 102 may be 1 adapted to engagethe lower edge of one of striker sup-- porting arms 102. With thisconstruction, when pneumatic cylinder 112 is so actuated as to extendits piston 115 downwardly, finger 117 drops with striker lifting arm 116away from the lower edge of the adjacent striker supporting arm andpermits arms 102 to rotate ina clockwise direction aboutshaft 103 so asto lower striker plate 101' into trough body 76. The operation ofcylinder 112 is automatically synchronized with the operation ofcylinder 98 which opens the gate 78 of nozzle 77, and with the movementof car 36 and trough 34, by the control system hereinafter described sothat the striker'plate enters the' forward end of the open body portionof the trough just as the gate opens to deliver lining material thereto.

Although the vertical position of the lower edge 111 of striker plate101 might be established by simply .pfilll'litv'.

ting the lower edges of stepped ends 107 of the striker plate to slideon the upper edges of the sidewalls of trough body 76, it is preferableto use a flanged roller 118 rotatably supported on a shaft 119 carriedby the forward ends of striker supporting arms 102 and supporting member105, which roller rests on the'upper edges of the trough withoutimposing any substantial amount of frictional resistance to the forwardand rearward 'movethe'desired amount. When the trough approaches the endof its forward movement, lower edge 111 of the striker plate comes intoengagement with the inclined edge of triangular plate 87 and is liftedthereby, carrying with it out of the trough any excess lining materialwhich may have accumulated behind the striker plate. A chute 120 havingan outwardly flared upper end is mounted at the forward end of'frame 37to receive any excess lining material removed from the trough by thestriker plate and deliver it to a conveyor (not shown) for appropriatedisposal. When the lining trough approaches the limit of its forwardmovement, pneumatic cylinders 98 and 112 are actuated to close gate 78'and raise striker plate'101 and its associated elements to theiroriginal positions shown in Figs. 11 and 12, these operations also beingautomatically controlled in a manner hereinafter described.

Returning now to the mold supporting and rotating portion of themachine, with particular reference to Fig. 17, it is customary toprovide a mold for casting bell and spigot pipe with a metallic insert121 at the bell end of the mold which establishes the contour of thebell end of In the embodiment of the invention illustrated, whereininsert 121' is shown as having two stepped surfaces, this meanscomprises a pair of metal tubes 123 and 124 which are supported'rforreciprocation in .a horizontal .direction Since it is desirable thatthese stepped surfaces be by suitable brackets 125 secured to the sameframework 126 as that on which trough supporting member 88 is mounted.The rear ends of tubes 123 and 124 are threaded into a manifold block127 which is .connected to the piston 128 of a pneumatic cylinder 129,also mounted on framework 126 in a horizontal position. Manifold block127 is provided with hoses 130 and 131 adapted to deliver compressed airto tubes 123 and 124, respectively. The inner end of tube 123 is fittedwith a downwardly directed nozzle 132 adapted to deliver a blast of airagainst the axially inner stepped surface 122 of insert 121, while tube124 is provided with a double nozzle 133 adapted to positions shown inFig. 17. Air under pressure is then supplied through hoses 130 and 131and tubes 123 and 124m nozzles 132 and 133, respectively, so as to blowoff of the stepped surfaces of insert 121 and the exposed end surface ofmold 32 any lining material that may be deposited thereon. When thelining trough has been dumped and starts its rearward movement out ofthe mold, cylinder 129 is again automatically actuated to retract tubes123 and 124, and the supply of air thereto is cut off.

Inasmuch as the apparatus of the present invention is intended to linemolds of diflferent diameters, means are provided for adjusting thelining mechanism so as to insure proper operation with molds ofdiflierent sizes. In the machine illustrated, this adjustment iseffected by varying the elevation of frame 37 and the elements supportedthereby, including lining trough 34, so that the lining trough ismaintained in a substantially coaxial position with respect to the moldto be lined.

As shown best in Figs. 7-10, frame 37 is supported above a fixedfoundation framework 134 by a parallel motion linkage comprising aplurality of pairs of upper links 135 and lower links 136 arranged inscissor relationship, the pairs of links positioned adjacent the frontend of frame 37 being so arranged that the hinge connections betweentheir upper and lower links move oppositely to the connections betweenthe links of the pairs adjacent the rear end of the frame when the frameis moved either upwardly or downwardly. In the apparatus shown in thedrawings, there are eight pairs of upper links 135 and lower links 136,four adjacent each end of frame 37, the upper end of each upper link 135being pivotally connected to frame 37 and the lower end of each lowerlink 136 being similarly pivoted to foundation frame work 134. The hingeconnections between the links of the four outboard pairs, i. e., thepairs nearest the ends of frame 37, are formed by a pair of transverselyextending shafts or pins 137, while the links of the four inboard pairsare hinged on the reducedend portions 138 of a pair of relativelymassive bolster members 139. Each hinge shaft 137 and the adjacentbolster member 139 are interconnected by a pair of horizontallyextending links 140 so as to insure that the hinge connections betweenthe respective pairs of links move in unison.

As indicated in Figs. 9 and 10, each bolster member 139 includes anenlarged central portion 141 which, in conjunction with tubular caps 142and 143 extending from the opposite sides thereof in fore-and-aftdirections, forms a housing for a nut 144 and the cooperating end of ascrew shaft 145.- The two nuts 144 are oppositely threaded, as are theends of screw shaft 145. Each nut 144 is securely fixed in its housingso as to transmit thereto and to the bolster 139 any thrust imposed onthe nut by rotation of screw shaft 145. Screw shaft 145 has whilemaintaining its horizontal position.

. 10 fixed thereto intermediate its ends a sprocket wheel 146 which isdrivably connected by a chain 147 to a similar sprocket 148 mounted onthe shaft of and driven by a reversible, three-phase A. C. electricmotor 149.

With the construction above described, frame 37 on which lining car 36and trough 34 are mounted may be raised or lowered to any desiredelevation by simply energizing motor 149 so as to rotate screw shaft inone direction or the other. Since the ends of shaft 145 and thecooperating nuts 144 are oppositely threaded, rotation of the shaft willmove the hinge connections of links 135 and 136 at opposite ends of theframe in opposite directions and thereby raise or lower the frame Themachine operator may determine when to deenergize motor 149 so as tostop the frame at the desired elevation by observing the position ofsome part of the vertically movable mechanism, such as the upper edge ofnozzle 77, relative to a fixed elevation indicator, such as a gauge 150which may conveniently be mounted on hopper 35 and suitably graduated toindicate the correct elevation for each different size of mold which themachine is adapted to line.

In order to insure that screw shaft 145 maintains a horizontal positionat all times and to absorb from nuts 144, thrust forces produced by themovements of car 36 on frame 37, the shaft is supported approximatelyhalfway between its ends by a double thrust bearing 151 the outer racesof which are rigidly held in a housing having laterally extendingtrunions 152 journaled in the free ends of a pair of parallel thrustabsorbing arms 153. The opposite ends of arms 153 are journaled on apair of pins 154 mounted at the upper ends of brackets 155 fixed tofoundation framework 134 Bearing 151 is held in fixed relationship toscrew shaft 145 by a pair of collars or nuts 156 which are threaded ontothe shaft and abut the opposite ends of the bearing. With thisconstruction, bearing 151 may adjust itself to the elevation of screwshaft 145 as the latter moves upwardly or downwardly with changes'in theelevation of frame 37, while still supporting said shaft in horizontalposition, and will transmit to the machine foundation through arms 153any thrust reactions resulting from the starting and stopping of liningcar 36.

The electrical and fluid pressure systems by which operation of theapparatus of the present invention is automatically controlled are shownschematically in Figs. 1'8, 19 and 20, and will be readily understoodupon consideration of the circuits therein illustrated in the light ofthe foregoing description and the following rsum of the operating cycle.

Assuming that detent-guide arms 48 and kickout arms 49 of the moldrotating mechanism 43 of each of lining machines L and L are in the uppositions illustrated in Fig. 6 and that an unlined mold 32 is rollingalong rails.31 leading to machine L the operation of the lattermachineis as follows, it being understood'that machine L 'operatessimultansously in the same manner on the partially lined mold which hasjust been ejected from machine L At this time, the switches and relaycontacts of the electrical system are in the positions illustratedinFigs. l8 and 19, hereinafter referred to as the normal positions.

As the mold approaches the lining station, it rolls over and opensnormally closed kickout down limit switch LS1 thereby deenergizing anormally energized control relay CR3 so as to open the latters normallyclosed contacts which are in series with limit switch LS1 and controlrelay CR3, close a set of normally open contacts which are in serieswith a normally open car in push button switch FBI, and open a third setof normally closed contacts to deenergize the normally energizedsolenoid S1 of a pneumatic pilot valve 157 (Figs. 18 and'ZO) which inturn actuates a four-way valve 158 controlling'the supply of hydraulicfluid to cylinder 62 so as to lower piston 61, detent-guide arms 48 andkickout ,arms 49 to the positions shown in .Fig.

and thereby delivermold 32 onto spinningrollers 40.

After visually inspecting the. interior of the mold, the machineoperator closes car in push button switch PB1 which energizes anormallydeenergized in travel starter relay SR1 and a normallydeenergized control relay CR1 (Fig. 18) and starts the automatic cycle.

In travel starter relay SR1 energizes thecircuit of motor 69 so as todrive lining car 36 in a forward or in direction and move lining trough34 into the mold. Relay CR1 energizes a normally deenergized controlrelay CR2 which in turn energizes a normally deenergized motor contactorrelay MR (Fig. 19) so as to start motor 45 and rotate the mold onspinning rollers 40. Energization of relay CR1 also energizes thenormally deenergized solenoid S2 of a four-Way valve 159 which controlsthe supply of air to cylinder 98 which opens gate 78 of nozzle 77through which the lining material is delivered into the trough, and tocylinder 112 which lowers striker plate 101 into the trough.

As the lining trough passes under nozzle 77, it receives'more liningmaterial than is required to form the desired thickness of lining, butstriker plate 101 removes the: excess material in the manner previouslydescribed. When the end of the open portion of lining trough 34 (definedby end plate 86) passes under the nozzle, the forward endof a switchtrip bar 160(Figs. 7 and 8), which is attached to lining car 36 at oneside thereof forward to its rear wheels 67, opens a normally closedlining material cutoif limit switch LS2 mounted on vertically movableframe 37 just to the rear of nozzle supporting framework 92. Opening oflimit switch LS2 deenergizes :relay CR1 which in turn deenergizessolenoid S2 of valve 159 and causes cylinders 98 and 112 to close gate78 and raise striker plate 101 out of the trough. Lining car 36continues to move forwardly until switch trip bar 160 opens a normallyclosed car'in limit switch LS3 mounted just forwardly of limit switchLS2 which deenergizes in travel starter relay SR1 and the forwardcircuit of car driving motor 69. Opening of the motor circuit alsoresults in application of solenoid actuated brakes 161' to the motorshaft, the brakes being applied by springs and released by solenoids BS(Fig. 18). in known manner. As lining car 36 is decelerated to a stop,switch trip bar 160 closes a normally open trough starting limit switchLS4 mounted forwardly of car in limit switch LS3 to energize a normallydeenergized trough dump starter relay SR2 through the normally closedcontacts of a time delay relay TD1. Simultaneously limit switch LS4energizes the-normally deenergized solenoid- S3 of a four-way valve-162which controls the supplyof air to cylinder 129 was -t0move blowouttubes123 and 124 into thelbell end" of the' rotating mold in order 'to directjetsof air, as previously described, on those areas which it isdesired-to keep clean of lining material. Limit switch LS4 alsoenergizes the normally deenergized solenoids S4 and-S5 of off-on valves163 and 164,-respectively, -to-supply compressed air to tubes 123'and124.

An' off-onpush' button'switch PB2 is provided so thatthe-machine-operator can control the energization of solenoid S4insaccordance with the type of mold being lined;

Trough dump starter relay SR2 energizes trough rotating motor 74" so asto rotate lining trough 34 in a clockwise direction as viewed from thefront and dump theliningwmaterial into the .mold.' When thetroughhas-been rotated to a substanti-al.inverted position, .a switchtripmember 165 mounted-on barrel 73 of the trough (Figs. 7 and8)actuates a double contact trough reset 'limitswitch LSS-the-normally'closed side of which I opensand .deenergizestrough-dumpstarterrelay SR2 while closure. of'its normally'open side energizes botha normally. deenergizedtroughreset starter relay SR3 and a normallydeenergized time delay relay TD2. Trough reset starter-relay SR3reversesthe'dir'ection of'trough motor 74'so as torotate the trough backtoits'original upright position; After a preset time interval, the normally closed contacts of time delay relay TD2 open to deenergizerelayCR2 which in turn deenergizes motor contactor relay MR and mold rotatingmotor 45 so as'to stop rotation of the mold, the time interval being soselected that the spinning of the mold continues until the resin of thesand-resin lining material has polymerized and bonded the sand particlestogether to form a relatively smooth, hard lining adherent to the moldwall.

When the lining trough returns to an upright position, switch tripmember'165 actuates a double contact trough stop limit switch LS6 thenormally closed side of which LS4 which returns to its normally openposition and thereby deenergizes solenoidsS3, S4 and S5 of valves 162,163 and 164, respectively, so as to result in the return of blowouttubes 123-and 124to their original positions shown in Fig. 13 and incutting olf of the supply of compressed air to said tubes.

The lining car continues to move in the out" or rearward direction untilthe lining trough is removed from the mold and the car approaches therear end of its run on tracks 68, at which time the rear end of switchtrip bar opens a normally open set of contacts of car out limit switchLS7 t0 deenergize out travel starter relay SR4'and car driving motor 69,whereupon the solenoid released brakes 161 are again spring applied tobring the car to a stop. I

As will be seen from the right-hand side of Fig. 18, which representsthe electrical control circuit of machine L and wherein all of theelements duplicating those of the circuit of machine L are designated bythe same reference characters plus prime marks, car out limit switch LS7of .machine L has a second set of normally closed contacts connected inseries with a second set of normally closed contacts of car out limitswitch LS7 of machine L and a relay CR4 and a time delay relay TD3 whichrelays have no counterparts in the circuit of machine L These two relaysare adapted to control the unloading of the line molds from the twomachines simultaneously, and cannot be energized until the lining carsof both machines have reached the end of their rearward movement andhave actuated both of car out limit switches LS7 and LS7. When thiscondition is satisfied and relay CR4 is energized, it energizes relaysCR3 and CR3 of the two machines which in turn energize solenoids S1 andS1 of the pilot valves 157 of valves 158 so as to actuated hydrauliccylinders 62 to lift detent-guide arms 48' and kickout arms 49 anddischarge the lined molds in the manner previously described. Time delayrelay TD3 opens its normally open contacts and deenergizes relay CR4after a very short interval, on the order of one second, followingenergization of said relay by closure of' thesecond sets of contacts ofcar out limit switches LS7 and LS7, but relays CR3 and CR3 remainenergized machines when actuated by molds rolling along rails 31, andthe control system is in condition to repeat the cycle.

It will be understood that various manually operable electrical controls(not shown) may also be provided to enable the machine operator to startand stop the mech-- anism at will, and to cause it to perform'variousoperations individually without going through the entire cycle.

Although only one specific form of apparatus embodying the invention hasbeen described and illustrated in the accompanying drawings, it willbeobvious that the invention is not limited to the exact structure shownbut is capable of a variety of mechanical embodiments. Various changes,which will now suggest themselves to those skilled in the art, may bemade in the form, .details of construction and arrangement of themechanical parts,

and in the electrical and fluid pressure means used for controllingvarious elements of the apparatus, without departing from the spirit ofthe invention. Reference is therefore to be had to the appended claimsfor a definition of the limits of the invention.

What is claimed is:

1. A machine for centrifugally lining cylindrical articles comprisingmeans for supporting a cylindrical article with its axis in asubstantially horizontal position and for rotating said article aboutsaid axis, means movable into and out of said article while it is beingrotated for delivering a quantity of lining material to the interior ofsaid article, including a container-for said material, a supportingframe on which said container is reciprocable in a substantiallyhorizontal path, and means for raising and lowering said frame relativeto said article supporting and rotating means to adjust the elevation ofthe path of movement of said container for operation with articles ofdifferent sizes.

2. A machine for centrifugally lining cylindrical articles comprisingmeans for supporting a cylindrical article with its axis in asubstantially horizontal position and for rotating said article aboutsaid axis, means for delivering a quantity of lining material to theinterior of said article, and means operative while the article is beingrotated for removing said lining material from selected areas of theinterior of said article.

3. A machine for centrifugally lining cylindrical articles comprisingmeans for supporting a cylindrical article with'its axis in asubstantially horizontal position and for rotating said articile aboutsaid axis, means for automatically controlling the delivery of unlinedarticles to said supporting and rotating means, means movable in asubstantially horizontal path into and out of an article while it isbeing supported and rotated by said supporting and rotating means fordelivering a quantity of lining material to the interior of saidarticle, and means controlled by the movement of said material deliverymeans for antomatically ejecting said article from said supporting androtating means upon completion of the lining operation.

4. A machine for centrifugally lining cylindrical articles comprisingmeans for supporting a cylindrical article with its axis in a fixed,substantially horizontal position and for rotating said article aboutsaid axis, means normally positioned above said supporting and rotatingmeans for receiving said article and lowering the latter onto saidsupporting and rotating means, means movable in a substantiallyhorizontal path into and out of said article while it is being rotatedfor delivering a quantity of lining material to the interior of saidarticle, and means operable automatically at the end of a predeterminedperiod of time after the lining material has been delivered into saidarticle for stopping the rotating action of said supporting and rotatingmeans.

5. A machine as defined in claim 4 including means responsive to themovement of an unlined article onto said said receiving and loweringmeans for causing the latter to lower said article onto said supportingand rotating means.

6. In a machine for centrifugally lining cylindrical casting molds, thecombination of a plurality of spinning rollers mounted on a pair ofparallel shafts for supporting a mold with its axis in a fixed,substantially horizontal position and for rotating said mold about saidaxis, mold run rails on which molds are rolled toward said spinningrollers for lining and on which lined molds are rolled away from saidrollers after lining, and means for delivering mold to and ejectingmolds from said spinning rollers comprising a plurality of paralleldetent-guide arms extending perpendicularly to the axes of said rollershafts from points intermediate said shafts outwardly to points beyondthe ends of said mold run rails from which the molds are delivered tosaid spinning rollers, a like plurality of parallel kickout armspivotally connected adjacent their inner ends to the inner ends of saiddetentguide arms and extending in the opposite direction thereto, theouter ends of said kickout arms being mounted for oscillatory movementabout a fixed axis parallel to the axis of said spinning roller shaftsand positioned beneath the ends' of said mold run rails onto which theof said detent-guide arms and kickout arms, the upper edges of saiddetent-guide arms and kickout arms forming mold rolling surfaces whenthe pivotally connected inner ends of said arms are raised tosubstantially the same level as that of said mold run rails and forminga V-shaped mold supporting cradle when said pivotally connected innerends are lowered below said plane, and means forming a variable fulcrumfor said detent-guide arms and so supporting said arms that the outerends thereof project above the level of said mold run rails in moldstopping position when the pivotally connected inner ends of saiddetent-guide arms and kickout arms are lowered to deliver a moldontosaid spinning rollers,

but drop below the level of said rails when the pivotally I the innerends of said kickout arms including upwardly projecting portions which,when said kickout arms and detent-guide arms are'raised with a moldsupported thereon, engage the outer surface of the mold at points offsetfrom the vertical axial plane thereof and cause the mold to roll olfsaid arms onto said mold'run rails when the upper edges of said kickoutarms are raised above the level of said rails.

8. In a machine for centrifugally lining cylindrical casting molds, thecombination, defined in claim 6 including fluid pressure actuated meansfor raising and lowering the pivotally connected inner ends of saiddetent-guide arms and kickout arms, and means for controlling theoperation of said fluid pressure actuated means mounted adjacent saidmold run rails in a position such that it is actuated by the rollingmovement of a mold along said rails as it approaches the mold rollingsurfaces of said detent-guide arms when the inner ends of said arms arein their raised positions.

9, A machine for centrifugally lining cylindrical molds adapted for usein centrifugally casting tubular metal articles comprising means forsupporting a mold with its axis in a substantially horizontal positionand for rotating said mold about said axis, an elongated trough fordelivering lining material to the interior of said mold, means formoving said trough axially into and out of said mold, means for fillingsaid trough with a measured quantity of lining material while saidtrough is being moved into said mold, and means for rotating said troughautomatically when the latter reaches the limit of its inward movementto deliver the lining material into the interior of said mold.

10. A machine as defined in claim 9 including a frame on which saidtrough is reciprocable in a horizontal direction, and means for raisingand lowering said frame relative to said mold supporting and rotatingmeans so as to adjust the height of said trough for operation with moldsof differentdiameters.

11. A machine as defined in claim 9 including means 15 for automaticallysynchronizing the axial and rotational movements of said trough.

12. A machine as claimed in claim 9 including means for automaticallysynchronizing the operation of said trough filling means with the axialmovements of said trough.

13. A machine as defined in claim 9 wherein said trough filling meansincludes a container for holding lining material, a gate for controllingthe delivery of lining material from said container to said trough, astriker member for establishing the amount of lining material retainedin said trough during its axial movement into said mold, means forsupporting said striker member, and means for so moving said supportingmeans as to move said striker member into and out of said trough.

14. A machine as defined in claim 13 wherein said striker supportingmeans is so constructed and arranged as to accommodate interchangeablestriker members of different sizes.

15. A machine as defined in claim 13 including means for automaticallysynchronizing the opening and closing of saidgate, and the movements ofsaid striker supporting means with the axial movements of said trough.

16. A machine as defined in claim 13 including fluid pressure actuatedmeans for opening and closing said gate and for moving said strikermember supporting means, and means for automatically controlling the operation of said fluid pressure actuated means in accordance with theaxial movements of said trough.

17. A machine as defined in claim wherein said means for'raising andlowering the trough supporting frame includes a plurality of hinged armspivotally connected at their lower ends to a fixed base and at'theirupper ends to said frame, and means for moving the hinged connectionsbetween said arms in unison to raise or lower said frame, said lastnamed means including ,a rotatable shaft having oppositely threaded endsengaging nut members carried by two of said hinge connections, and meansfor rotating said shaft.

18. A machine as defined in claim 17 including means for preventing thetransmission to said threaded shaft of thrust reactions resulting fromthe axial movements of said trough on said frame.

19. In. a machine for centrifugally lining cylindrical articles, thecombination of means for supporting a cylindrical article with its axisin a substantially horizontal position and for rotating said articleabout said axis, an

elongated trough for delivering lining material to the in- 16== troughto dump thelining material into the interior of said article and toreturn the trough'to upright position after the dumping operationfandelectrical control means for automatically energizingt'he reversedriving circuit of said-motor upon return of said trough to uprightposition.

20. In 'a machine for centrifugally lining cylindrical articles, thecombination defined in claim 19 including an electric motor'for rotatingsaid trough, and electrical control means forautomatically energizingsaid trough rotating motor after the forward driving circuit of said cardriving motor has been deenergized.

21. In a machine'for centrifugally lining cylindrical articles, thecombination defined in claim 19 including a gate for controlling thefilling of said trough with lining material, means for opening andclosing said gate, electrical control means for simultaneouslyenergizing the forward driving circuit of said car driving motor andeffecting opening of said gate, andelectrical control means foreffecting closure of said gate just'before the forward driving circuitof said car driving motor is deenergized.

22, A machine for centrifugally lining cylindrical articles comprisingmeans for supporting a cylindrical article with'its axis in asubstantially horizontal position and for rotating said article aboutits axis, means movable into and out of 'said article from one-endthereof while it is being rotated for delivering lining material to theinterior-of said article, andmeans movable into and out of the'oppositeend of said article while the article is being rotated for preventingthe adherence of said lining material to selected areas of the interiorof said article. I

23. A machine as defined in claim 22 wherein said last named meansincludes a nozzle for directing a blast of air against said selectedareas.

24.'A machine as defined in claim 22 including means for automaticallysynchronizing the movements of said lining material delivery means andsaid means for preventing the'adherence oflining material toselectedareas of the interior'of said article.

References Cited in the file of this patent UNITED STATES PATENTS1,700,697 Draper Jan. 29, 1929 1,783,094 Moore et al. Nov. 25, 19301,913,757 Hannon June 13, 1933 1,961,260 Ukropina June 5, 1934 1,963,146Russell et al June 19, 1934 1,963,148 Russell et al. June 19, 19342,133,015 Boylan et al. Oct. 11, 1938 2,244,651 Goebel et al. June 3,1941 2,272,073 Von Sydow et al. Feb. 3, 1942 2,523,558 Cavallier Sept.26, 1950 2,529,291 Graham' Nov. 7, 1950 2,602,415 a Hall July 8, 19522,731,690 Coupland et al. Jan. 24, 1956 2,747,539 Peffer May 29, 1956

